A study on the effect of Gynostemma Pentaphyllum leaves extracts reported that an ethanol extract of Gynostemma Pentaphylluim leaves showed potent hypoglycemic effect in animal model of type 2 diabetes, and was effective at the amount of 100 mg/kg [Reference material: Yeo J Y, et al., 2008, Potential Hypoglycemic Effect of an EtOH Extract of Gynostemma pentaphyllum in C57BL/KsJ-db/db Mice, J. Medicinal Food, 11: 709-716].
Further, Gynostemma Pentaphyllum leaves extracts has been suggested to improve metabolic disease including obesity, diabetes, and hyperlipidemia, etc. by increasing the activity of AMP-activated protein kinase (AMPK), and as a major preparation method of such a Gynostemma Pentaphyllum leaves extract, an extraction method increasing the contents of damulin A and B through ethanol extraction and subsequent high temperature treatment is known (Korean Patent No. 10-0930580). Another example is Korean Patent Publication No. 10-2014-0108621 relates to a composition for the treatment or prevention of type 2 diabetes, obesity, or hyperlipidemia, comprising gypenoside extract of Gynostemma Pentaphyllum leaves containing one or more dammarane triterpenoid saponin compounds selected from the group consisting of gypenoside UL1, gypenoside UL2, gypenoside UL3, gypenoside UL4, gypenoside UL5, gypenoside UL6, gypenoside UL7, and gypenoside XLVIII, as an active ingredient.
It is known that the efficacy of saponin increase when saponin is converted to small molecular saponin. Various methods such as fermentation, enzyme or heat treatment, etc. have been reported for the conversion to small molecular effective saponin. However, if the fresh leaves of Gynostemma Pentaphyllus are used as is, the precursors of small molecular effective saponin, which are diversely present in the fresh leaves, are not sufficiently activated. Thus, if the leaves are extracted according to such a method, the efficacy of the extract would be low, and it has been confirmed by years of researches that even if the processes such as heat treatment, etc. are carried out after extraction, the efficacy would not be guaranteed. Further, if the leaves are fermented or treated with enzyme, small molecular effective saponin content increases to some extent; however, the process time and cost of production increase due to the additional process.
Benzopyrene is generated during the preparation process of the Gynostemma Pentaphyllus leaves extracts. Benzopyrene is a yellow crystalline solid which belongs to polycyclic aromatic hydrocarbon (PAH) and is produced by incomplete combustion at 300˜600° C. Benzopyrene typically exists in coal tar, car exhaust emission, cigarette smoke, etc., emitted into the environment through incomplete combustion, and can spread far from the source of origin due to its high stability in the atmosphere. Benzopyrene also presents in the uncooked or unprocessed foods such as agricultural products, fishes and shells, etc., and can be produced when heating foods at high temperature due to degradation of carbohydrate, protein, lipid, etc., which are the main ingredients of foods. As such, body is exposed to benzopyrene through contaminated water, foods, and atmosphere, and various benzopyrene metabolites metabolized in the body are known as causing cancer by adducting to DNAs.
Further, benzopyrene is even more problematic due to its long residual period and strong toxicity, and is in the center of world-wide attention as a possible carcinogen as well as an endocrine disruptor. Also in the food sector, problems have arisen from benzopyrene, and recently in Korea, benzopyrene has been detected in the processed ginseng products, etc. such as heat-treated red or black ginseng, etc. and thus, there is an increased interest in the technology of reducing benzopyrene.
Therefore, a novel method to reduce the amount of benzopyrene while increasing dammarane small molecular effective saponin compounds such as ginsenoside Rg3, gypenoside L, gypenoside LI, etc., which are the main active physiological ingredients of Gynostemma Pentaphyllus leaves extracts is required.